Supercharging device for internal combustion engines



y 1962 G. GARCEA 3,036,563

SUPERCHARGING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed July 13, 1959 United States Patent fifiice 3,3h,5h3 Patented May 29, 1962 The present invention relates to a device for the control of fluid-dynamic (booster) compressors for the supercharging (boost feeding, boosting) of internal combustion engines.

It is known that in general fluid-dynamic compressors for the supercharging of internal combustion engines of automotive vehicles, if they are not controlled directly by a discharge gas turbine, require considerable multiplication of the number of rpm. with respect to the dr ive shaft, as well as a considerable possibility of variation of this transmission ratio, to adapt the characteristics owned by the compressor to those of the engine in the various conditions of operation. If using wheelworks as transmission means, considerable inconveniences are met, such as excessive noise of the gearings, and the difiiculty of realizing the variation of the transmission ratio, with automatic choice of the ratio in question. A control by V-belts would be preferable, which solution however also has inconveniences and difficulties. l

it is an object of the present invention to eliminate said inconveniences, by creating at the same time advantages over the devices of known kind; namely, the invention consists in the coupling of a hydraulic turbine to the highsueed shaft of the compressor; said turbine receives fluid under pressure from a hydraulic pump which for the purpose is coupled with the internal combustion engine.

Thereby elevated transmission ratios are obtained by means of a device without any gears and consequently noiseless operation. The transmission ratio can be varied by utilising a pump with variable cylinder space; the automatic adjustment of delivery as obtained by varying the cylinder space, may be etfected by utilising the very delivery pressure of the pump in such a way for instance as to realize the maximum supercharging ratio, corresponding to the rpm. of the internal combustion engine with which in particular there is required the highest increase of the torque; in that case, the control action upon the device, by the driver, can be obtained by means of a supplmental stroke of the accelerating pedal in addition to the throttle position being completely open. By connecting the pedal of the accelerator With a convenient lever for adjusting the pressure, fixed to the pump, one will obtain consequently a progressive increase of the hydraulic pressure in the device and consequently of the supercharging ratio.

The ratio of transmission may be varied as an alternative of the solution just described, by utilising a pump with constant cylinder space coupled with a turbine whose characteristic curve can be varied by acting upon the cross-section and upon the shape of the distributor or of the nozzle according to whether it is a total admission (for instance centripetal) or Pelton wheel turbine,

Also in this case the last part of the stroke of the accelerator pedal will define the magnitude of the hydraulic power transmitted and, therefore, the supercharging ratio.

In whatsoever manner the variation of the ratio of transmission is effected, under all conditions of operation with throttle not completely open the automatic device can easily warrant a minimum hydraulic pressure and, therefore, a determined speed of rotation of the compressor so as to utilise the same as an agitator-mixer and homogeniser of the mix in the case of a carburettor engine; useless to say that under those conditions the power absorbed by the group is completely negligible so that there remain only the advantages relative to a better distribution of the mixture.

With respect to the solutions mentioned above wherein the dragging of the compressor is effected by means of the coupling with a discharge gas turbine, the instant solution affords a definite advantage from the point of view of promptness of response to the action upon the accelerator pedal; the time necessary in order that the rotor of the compressor assumes the normal speed is negligible in practice while the slowness of attaining the normal speed represents a negative characteristic of the compressor driven by discharge gas turbine. I

Another advantage of the instant solution is that of greater facility in dosing automatically the maximum supercharging at the carious speeds in such a way as to obtain the most suitable working curve of the engine: the discharge gas turbine generally can supply only supercharging growing with the growing speed and, therefore, elevated torque only at elevated speeds.

As is known the discharge gas turbine affords some advantage from the point or" view of specific consumptions at full power, but in the case considered of application to automotive vehicles wherein the super-power is required only for very short periods of time the disadvantage for the instant solution is not sensible; on the contrary it is possible to attain an advantage at partly reduced speeds (at which employment prevails) thanks to the greater homogeneity of the mixture.

An embodiment of the device according to the invention is hereinafter described merely by way of example, with reference to the accompanying diagrammatical drawing or" which:

FIG. 1 shows a front view of an internal combustion engine with a carburettor, on which said supercharging device is applied;

PEG. 2 shows the same in side view and FIG. 3 shows the same in plan view.

On the engine 1 is applied a hydrostatic pump 2 connected to the drive shaft by means of a belt indicated with 3.

A turbine indicated with 5 is connected with the pump by means of the conduits 4-; rigid with the body of the turbine 5 is the body of the centrifugal compressor 6; with 7 is indicated the carburettor; with 8 is indicated a silencer filter.

To the pedal of the accelerator 9 is fixed the small lever 1%, connected to the rod It for the control or" the normal throttle of the carburettor; to said pedal 9 is also fixed a small lever 12 to which is connected a link l3 connected in turn to a control lever on the adjusting device of the hydrostatic pump 2.

The control of the pump 2 thus takes place by means of its connection to the drive shaft through the belt 3; through the conduits d the oil is conveyed to the turbine 5 and returns from the turbine to said pump. The centrifugal compressor 6 sucks the mixture from the carburettor 7: the air arrives at the carburettor from outside through the silencer filter 3.

The compressed mixture leaving the compressor is sent to the cylinders by means of a normal induction manifold.

The same pedal of the accelerator 9, which controls the normal throttle of the carburettor, through said lever it? and rod it controls also, through the small lever 12 and the link 13, a control lever on the adjusting device of the hydrostatic pump 2.

As precedingly mentioned, the essential feature of the present invention consists in the coupling of a hydraulic turbine with the high-speed shaft of the compressor,

Of course it should be understood that in addition to the example of embodiment of the whole device as de- -31 scribed above, there are possible variants, without departing from the scope of the invention.

I claim:

1. In a supercharger for internal combustion engines, of the kind having a shaft driven charge-compressor and hydrostatic pumping means driven by said engine for actuating said compressor, the combination comprising a hydraulic turbine Wheel mounted coaxially on the charge-compressor shaft and fed in closed circuit by operative fluid compressed by said pumping means, flow 10 controlling means for said operative fluid, said flow controlling means being actuated in response to an accelerator pedal of said engine.

2. In a supercharger for internal combustion engines,

of the kind comprising a shaft driven charge-compressor and hydrostatic pumping means driven by said internal combustion engine for actuating the compressor, the combination comprising a hydrostatic turbine Wheel mounted coaxially on the charge compressor shaft and fed in closed circuit by operative fluid compressed by said pumping means, floW controlling means for said pumping mean, and means for actuating said flow controlling means.

References (Iited in the file of this patent UNITED STATES PATENTS 2,774,342 Schilling Dec. 18, 1956 

